Embodiments of the inventive concept described herein relate to a method and apparatus for interference-aware resource-sharing scheme for multiple device-to-device (D2D) group communications underlaying cellular networks.
D2D communications have the advantages of supporting a higher date rate, lowering communications delay, and reducing energy consumption, which has been considered as a key technology for future 5G mobile communication systems. D2D communications are regarded as key technology for 5G systems. Therefore, D2D communications may be helpful in accomplishing low energy consumption as well as high data rates and low communication delays. In D2D communications, D2D pairs can operate in two modes: dedicated resource with direct link, and reusing resource with direct link.
Since the mode of reusing resource with direct link mode potentially leads to better network performance in terms of spectrum efficiency and user access rate, especially when the traffic loads in the network are heavy. Thus, it has become the main target for the D2D communications.
However, in reusing resource with direct link mode, D2D pairs share the same frequency resource with cellular users (CUEs). This generates Co-Channel Interference (CCI) among D2D pairs and CUEs to guarantee more complicated QoS requirements. Therefore, the CCI between D2D pairs and CUEs is the main challenge for D2D communications underlaying cellular networks.
Multiple CUEs and D2D pairs may be co-existed in a cell. Multiple D2D pairs forms a group for sharing the frequency resource and forms multiple D2D groups in a cell. The eNB has an Adaptive Antenna Array (AAA).
FIG. 1 illustrates a system model with multiple D2D pairs in a cellular network.
CUEs and D2D groups/pairs share the same frequency resources, whereas users' frequency resources may be shared by one D2D group/pair at most.
FIGS. 2A to 2C illustrate intra-cell downlink interference scenarios.
All CUEs and D2D pairs coincidently operate and other D2D pairs of the same group share the same frequency resource. Hereupon, as illustrated in FIGS. 2A to 2C, it needs to consider 3 types of Down Link (DL) intra-cell interference.
Referring to FIGS. 2A to 2C, there are 3 types of DL intra-cell interference: (a) interference to D2D from eNB Tx; (b) interference to a user from D2D Tx; and (c) interference to another D2D Rx from D2D Tx.
IA is an effective interference management approach that has been proposed. By using IA, multiple D2D pairs forms a group to share the same Resource Blocks (RBs). This improves the system throughput and reduces interference among different D2D pairs in a group. Adaptive antenna array (AAA) is an advanced technology that offers a significantly improved solution to reduce the interference and improve the system capacity.
Therefore, it is suitable for the coexisting D2D pairs and CUEs when they are sharing the same frequency resources, and it is possible to obtain zero gain outside of half power bandwidth (HPBW).
As at most one D2D group shares RBs with CUEs, thus the interference between the D2D pairs and CUEs is the main target to be managed. Therefore, it is necessary to improve cell performance and to propose a spectrum sharing technique for solving the issues of CCI.